Many types of specimen receptacles are known in the art. Automatic analyzing apparatus for testing fluid samples are also well known in the art, including the utilization therewith of throw-away specimen cups formed of plastic, and having individual caps, adapted for snap attachment to the respective separate specimen cups and an associated cap, into the analyzing apparatus, and so far as applicant knows, heretofore such specimen cups and associated snap-on caps, have been provided as individual, separate articles, so that loading and unloading ]is quite time consuming and tedious. The individual prior art specimen cups have also been somewhat inadequate by reason 1 that they retain substantial residues of quantities of serum which is lost upon disposal of the cup which becomes substantially costly in mass testing procedures; also the prior art cups are impractical when limited quantities of serum are only available.